1. 1 Computer Networks IPv6

2. 2 Motivation The primary motivation from changing the IP datagram format is to increase the size of the useable address space from 32 bits to 128 bits. Secondary reasons include routing improvements, simplicity in header format and even to bring back some of the end-to-end principles that are being lost due to NAT and firewalls.

3. 3 IPv6 Standardized in RFC 2460 Extends Addresses from 32 to 128 bits Streamlined header format Routers no long fragment packets New flow labeling capability Enhanced options design

4. 4 IPv6 Header Format

5. 5 Options Move Out

6. 6 Various Protocol Changes ICMP Streamlined IGMP now part of ICMP Changes to upper layers New DNS record type AAAA RIPv6 OSPFv6

7. 7 Fragmentation Changes Fragmentation is no long done by routers Hosts musts discover the path MTU This is a significant change from IPv4!

8. 8 Addressing Changes Using IPv4 dotted decimal notation 105.220.136.100.255.255.255.255.0.18.128.140.10.255.255 IPv6 uses colon hexadecimal notation 69dc:8864:ffff:ffff:0:1280:8c0a:ffff With zero compression ff0c:0:0:0:0:0:0:b1 becomes ff0c::b1 IPv4 addresses start with 96 zeroes No more broadcast, new anycast address

9. 9 Address Assignment Standard assignments IPv4 compatibility IPX addresses Link, site and multicast addresses Auto configuration Serverless autoconfiguration is possible Simple renumbering is possible

10. 10 Making the Transition 6Bone - current testbed Dual stacks Tunnelling Address Translation Lots of software changes! Will take years, but may be taking off now

11. 11 Final Thoughts What ’ s taking so long? NAT, CIDR, killer applications Might help return end-to-end principles Difficult to upgrade all hosts Other benefits and problems?